Shower stall base



FIG. 1 is perspective view of a shower stall base according to thisinvention;

FIG. 2 is a front elevational view thereof, the back elevational viewbeing the same;

FIG. 3 is a top plan view thereof;

FIG. 4 is right end elevational view thereof;

FIG. 5 is a left end elevational view thereof;

FIG. 6 is a bottom plan view thereof;

The ornamental design for a shower stall base, substantially as shownand described.